Corrected entry: Listen very closely to the scene in which Alex and the other dancers are bantering in the dressing room. You'll notice that one of them addresses her as "Angela".
Corrected entry: When Alex is watching the ballet on TV, she does a turn and spills a drink on her shirt. She wipes it off, but in the next shot there aren't any marks on her shirt.
Correction: After she spills the drink on her, there is never another shot of her in that top. It cuts to the scene of her in her black leotard, dancing to 'Maniac.' Anyway, she spills the drink on her skin (down her top) not on her top.
Correction: They could have forgotten her name or maybe it could be a nickname, but since Alex is played by Jennifer Beals, it's no clash with the actress' name, so it's really only a error made by the character, and not really a proper movie mistake.
Hamster
Actually, the dancer calls her "Angel," not "Angela."